|Identity conditions: A) Theories differ in the domain of assumed objects and the use of terms. Therefore, it is not self-evident that the identity of an object can be determined when different theories refer to this object. One problem is, for example, the coarser or finer classification of properties in the different theories.|
B) If objects are characterized intensionally – e.g. "the oldest present person" - the reference changes with the context. In this case, the context must be used to determine the identity.
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Uniqueness condition/W-questions/answer/Hintikka: the condition that something is a complete and unambiguous answer to a who-question (ambiguous) is, first, that (8) must imply (7)
(6) Who is the man over there?
(7) I know who the man over there is.
E.g. it is Sir Norman Brook.
(8) I know the man there is Sir Norman Brook.
Problem: the step from (8) to (7) is that of an existential generalization (EG).
Problem: for that we need an additional premise. E.g.
(13) (Ex) Ki (Sir Norman Brook = x).
(Non-mirrored quantifier, perceptually)
"I know who Norman Brook is."
HintikkaVsQuine: Quine does not recognize the role that my uniqueness conditions play:
Quine: Quine says that these conditions can also be transferred to belief, knowledge, etc.
Quine: Hintikka wants the subject to know who or what the person or thing is. Whom or what the term designates.
HintikkaVsQuine: he thinks I would only use one kind of uniqueness condition.
Solution: the semantic situation shows the difference: the relation between the conditions for different propositional attitudes (belief, seeing, knowledge) is one of analogy, not of identity.
Solution: the sets of compatible worlds are respectively different ones in the case of knowledge, seeing, memory, belief!
Identification/belief/Quine/QuineVsHintikka: every world of belief will contain innumerable bodies and objects that are not recognizable at all, simply because the believer believes that his world contains a countless number of such objects.
Identity: Questions about the identity of these objects are meaningless.
Problem: if you quantify in belief contexts, how should one exclude them?
Solution: one would have to limit the range of the variables to such objects, over which the subject has a sufficiently clear idea.
Problem: How should one determine how clear these ideas must be?
HintikkaVsQuine: the solution is quite simple when we quantify over individuals in doxastic worlds:
E.g. Operator: "in a world w1, compatible with everything, Jack believes":
Solution/Hintikka: we can quantify over inhabitants of such worlds by simply using a quantifier within the operator.
((s) i.e. that Jack, but not we differentiate?).
Problem: it could be that we want to consider the inhabitants as our neighbors from the actual world w0. ("Qua neighbors").
Hintikka: but that is a problem for itself and has nothing to do with uniqueness conditions.
Problem: it rather lies in the notation of the conventional modal logic, which runs from the outside to the inside and which does not allow the evaluation process, to ever turn around so that it runs from the inside outwards.
Solution/Saarinen: the solution is "retrospective" operators.
Solution/Hintikka: it may be that we can trace back an individual from w1 to w0, even if it does not fulfill the uniqueness conditions. (These require that an individual is identifiable in all worlds.)
HintikkaVsQuine: the latter is mistaken that the question of identity is meaningless if the uniqueness conditions are not all fulfilled.
On the contrary: it has to be meaningful so that we are able to see that the conditions are not fulfilled!
Uniqueness condition/Hintikka: if the uniqueness condition is not fulfilled, it means only that we cannot find an individual in every world.
Truth conditions/Uniqueness conditions/Hintikka: the truth conditions of the uniqueness conditions are very different from the truth conditions for other types of the most simple sentences.
World lines/Hintikka: world lines can therefore be drawn in different ways, without tipping over the remaining semantic situation.
Jaakko and Merrill B. Hintikka
The Logic of Epistemology and the Epistemology of Logic Dordrecht 1989
J. Hintikka/M. B. Hintikka
Untersuchungen zu Wittgenstein Frankfurt 1996